1. Field of the Invention
The present invention relates to an optical connector. Specifically, the present invention relates to an optical connector that optically connects optical members and optical devices by use of optical reflection in the optical connector.
2. Description of the Related Art
Japanese Patent Application Laid-Open Publication No. 2001-174671 (Patent Document 1) and Japanese Patent Application Laid-Open Publication No. 2007-121973 (Patent Document 2) disclose a conventional optical connector that optically connects optical fibers provided parallel to a circuit board to an optical element on the circuit board. Such an optical connector optically connects the optical fibers to the optical element by use of internal reflection. The internal reflection is a reflection of light in an optical connector body, through which the light passes. The reflection is generated in an interface between the body and an exterior thereof (such as air).
FIG. 1 shows an optical connector (optical element module) 71 of Patent Document 1. The optical connector 71 includes a transparent frame 76, which is mounted on a circuit board 73. The frame 76 is provided with a convex portion 75. The convex portion 75 is formed in a rectangular triangle having an incline 75a inclined at 45 degrees with respect to the circuit board 73 and a vertical surface 75b vertically formed with respect to the circuit board 73. An optical fiber 74 contacts with the vertical surface 75b of the convex portion 75. The incline 75a of the convex portion 75 is an internal reflection surface (the internal reflection surface is also shown by 75a). A reference sign 74a represents a core of the optical fiber.
Light emitted from a tip of the optical fiber 74 in the above-mentioned optical connector 71 enters the convex portion 75 from the vertical surface 75b, and is reflected (internally reflected) by the incline of the convex portion 75, i.e. the internal reflection surface 75a. The light reflected by the internal reflection surface 75a travels downwardly (i.e. perpendicularly) in the figure, and enters an optical element 72 on the circuit board 73. Alternatively, the light emitted from the optical element 72 enters the optical fiber 74 in the same optical path.
In order to enhance light collection efficiency in each end surface of the optical fibers and a light receiving surface of the optical element, the internal reflection surface 75a may be configured to be curved (refer to FIG. 3 of Patent Document 1).
The optical connector of Patent Document 2 includes an optical connector body made of a transparent material. The optical connector body is mounted on a circuit board. The optical connector body has bottomed holes formed parallel to the circuit board. Optical fibers are inserted into the bottomed holes. In addition, the optical connector body has a concave portion provided in front of tips of the optical fibers inserted into the bottomed holes. The concave portion has an incline. The incline faces the tips of the inserted optical fibers, and is inclined at 45 degrees with respect to each optical axis of the optical fibers. The incline functions as an internal reflection surface. That means light emitted from the tips of the optical fibers is reflected (internally reflected) by the incline toward the circuit board, and enters an optical element on the circuit board.